Home K3S High Performance Transceiver Firmware and Utility

K3S High Performance Transceiver Firmware and Utility

Current K3, K3/0 Mini and K3s Production Firmware  

K3 MCU 5.67 / DSP 2.88 / FPF 1.26, 1-22-2019

All K3s radios ordered today will have Product Firmware loaded as they come out of the box.  Monitor the Elecraft Email Reflector where announcements are made when new releases become available.  

Elecraft delivers new features in firmware.  As a result, you should consider the Release Notes as an extension of the Owners Manual.  Documentation for the new features will be found there and will not appear in the Owner’s Manual until the next major manual revision is released.

Current Production Firmware Release Notes

  • 6 M GAIN REDUCTION (FOR USE WITH KPA3A): In some cases the KPA3A may have more gain than necessary on 6 meters. As a precaution, all radios using a KPA3A (instead of the older KPA3) should be configured to insert some attenuation. See instructions below. No hardware modifications are required.
INSTRUCTIONS: [Do this only on a K3S, or a K3 that has a KPA3A installed.]
1. Select the 6 meter band.
2. Connect a dummy load rated at 50 W (or higher) to the transceiver.
3. Set the PWR control to 50 watts.
4. Place the ATU in bypass mode.
5. Locate the CONFIG:TUN PWR menu entry. Set the value to NOR using VFO A.
6. Locate the CONFIG:TXGN HP menu entry.
7. Tap the '8' switch (NR) once to add "ATN6" to the parameter display on VFO A. (Tapping it a second time would return to the original non-attenuated setting.)
8. Exit the menu.
9. Hold TUNE to do automatic power calibration on 6 meters at the 50 W level. After a few seconds, tap XMIT to terminate the TUNE operation.
NOTE: If you have difficulty reaching full power on 6 meters after making this change, it could be because your PA module is actually a KPA3, not a KPA3A. In this case, re-do the above procedure, changing the TXGN HP menu setting back to the original (i.e., without "ATN6" showing). (Max. power output at 50 MHz is specified at 100 W +/- 1 dB, typical. 1 dB below 100 W is approx. 90 W. See Specifications for max output at 51 MHz and higher.)


Important - Please read before installing the latest Production Firmware

If you have firmware older than indicated below, please be sure to follow the steps below.

  • MCU 5.10 (or later): Re-run the 50-Watt gain calibration step on all bands one time. Once this has been done, there is no need to do it again when loading releases above 5.10.
  • MCU 4.67 (or later): Must be loaded with  K3 Utility, Version or later

Production Firmware Installation Instructions are found in the Utility

  • All Production Firmware is loaded with the K3 Utility.  It will take care of the download and installing Production Firmware
  • Before loading Production Firmware, please ensure you have installed the latest version of the K3 Utility.
  • See the Help → Getting Started pull-down menu in the K3 Utility for the steps to install firmware in your K3, K3/0 Mini, K3s.


Download and Install the K3 Utility for your Operating System

Follow the links below to download and install the latest version of the Utility for your Operating System.

You will be connecting the K3, K3/0 Mini, K3s to the computer with a USB A-to-B cable that was included with the K3, K3/0 Mini, K3s when it was shipped from the factory.

Minimum Operating System Requirements for Elecraft Utilities:

Microsoft Windows: XP Service Pack 3 or later, including Vista, 7, 8, and 8.1 and 10.

Apple Mac: OS X 10.6 (Snow Leopard) or later  



K3 Utility (Windows Version  January 17, 2020

  • Note:  This K3 Utility version can be used to load K3 MCU versions 1.32 and above to your K3.
  • This is an auto-installer file.  Download and run the file from the above link.
MacIntosh K3 Utility (64bit MAC OS X Version  September 12, 2019
  • Note: This K3 Utility version can be used to load K3 MCU versions 1.32 and above to your K3.
  • This K3 Utility version is REQUIRED to load K3 MCU versions 1.79 and above to your K3.
  • Files are in universal binary in .zip file
X86 Linux K3 Utility (64bit Linux .tgz Version  September 12, 2019
  • Note: This K3 Utility version can be used to load K3 MCU versions 1.32 and above to your K3.
  • This K3 Utility version is REQUIRED to load K3 MCU versions 1.79 and above to your K3.
  • Files are in TAR archive (gzip-compressed) format.


The following libraries and dependencies should be installed on your Linux distro:

GTK+ 2.8 or later, glibc-2.4, libstdc++.so.6 and cURL. 64-bit Linux requires 32-bit compatibility libraries.

Installing the FTDI driver Follow this link to the FTDI Site for drivers: http://www.ftdichip.com/Drivers/VCP.htm

Depending on the Operating System you have, the driver needed for the Utility to communicate with the K3, K3/0 Mini, K3s will need to be loaded.

All Elecraft products in production use the FTDI chipset for this function. The FTDI driver allows your computer to create a virtual COM port so that the Utility can communicate with the Elecraft product.


Beta Firmware Installation and Release Notes

Beta Firmware Release Notes

No Beta Firmware candidate at this time

Beta Test Firmware Installation Procedures

NOTE: Beta test firmware may have new issues that we haven't caught during field testing. Please report them to support@elecraft.com.

A little more detail

We make it a little harder to load Beta firmware mainly because we want you to be sure you want to do this. Beta firmware means that, while the K3, K3/0 Mini, K3s engineering team has fully tested the firmware, it has not yet been deemed ready for Production status. You can always return to the last firmware you have downloaded by following the steps in the K3 Utility’s Help section.

To load Beta Firmware, follow the steps below:

    1.  Create a new folder for the beta firmware on your Desktop or some other easily found location. Use the a different folder than the default folder found in the Firmware tab of the Utility. In this way, you can revert to the last Production firmware easily.

      2.  Now, we will download the firmware in Zip file format. In a web browser, type in this URL:  https://ftp.elecraft.com/K3/firmware/beta 

      If you do not see the correct version of the zip file, press the RELOAD/REFRESH button on our browser to update your browser cache.    

        3.  Right-click on the .zip file containing the beta firmware (e.g. k3fwXrYZ.zip for revision MCU X.YZ and all associated files). Save the file to your beta folder you just created.

          4.  Unzip the files into the beta folder.

            5.  Enter the path to the beta folder in K3 Utility → Firmware tab → "Local folder for firmware files".

              6.  After you have made the change in Step 5, make sure you *DO NOT* check the K3 Utility box titled "Copy new files from Elecraft server". This will overwrite the Beta firmware if clicked.

                7.  Connect the K3, K3/0 Mini, K3s to your computer and be sure it is turned on. Select the Firmware tab and Click on "Check versions now" button.

                  8.  Review the release notes. To find them, select the "Help" pull-down menu.

                    9.  Click "Send all firmware to K3." This will cause the firmware to be sent to the K3, K3/0 Mini, K3s. You will see that the K3, K3/0 Mini, K3s appears to restart itself. Monitor the Activity Log until it is complete.

                      10. After completing a new software download to your product, please power cycle the K3, K3/0 Mini, K3s OFF and then back ON before using it.


                        Please report any new firmware issues to support@elecraft.com